src/util/ralloc.c

   1 /*
   2  * Copyright © 2010 Intel Corporation
   3  *
   4  * Permission is hereby granted, free of charge, to any person obtaining a
   5  * copy of this software and associated documentation files (the "Software"),
   6  * to deal in the Software without restriction, including without limitation
   7  * the rights to use, copy, modify, merge, publish, distribute, sublicense,
   8  * and/or sell copies of the Software, and to permit persons to whom the
   9  * Software is furnished to do so, subject to the following conditions:
  10  *
  11  * The above copyright notice and this permission notice (including the next
  12  * paragraph) shall be included in all copies or substantial portions of the
  13  * Software.
  14  *
  15  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
  16  * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
  17  * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL
  18  * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
  19  * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
  20  * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
  21  * DEALINGS IN THE SOFTWARE.
  22  */
  23
  24 #include <assert.h>
  25 #include <stdlib.h>
  26 #include <stdarg.h>
  27 #include <stdio.h>
  28 #include <string.h>
  29 #include <stdint.h>
  30
  31 /* Android defines SIZE_MAX in limits.h, instead of the standard stdint.h */
  32 #ifdef ANDROID
  33 #include <limits.h>
  34 #endif
  35
  36 /* Some versions of MinGW are missing _vscprintf's declaration, although they
  37  * still provide the symbol in the import library. */
  38 #ifdef __MINGW32__
  39 _CRTIMP int _vscprintf(const char *format, va_list argptr);
  40 #endif
  41
  42 #include "ralloc.h"
  43
  44 #ifndef va_copy
  45 #ifdef __va_copy
  46 #define va_copy(dest, src) __va_copy((dest), (src))
  47 #else
  48 #define va_copy(dest, src) (dest) = (src)
  49 #endif
  50 #endif
  51
  52 #define CANARY 0x5A1106
  53
  54 struct ralloc_header
  55 {
  56 #ifdef DEBUG
  57    /* A canary value used to determine whether a pointer is ralloc'd. */
  58    unsigned canary;
  59 #endif
  60
  61    struct ralloc_header *parent;
  62
  63    /* The first child (head of a linked list) */
  64    struct ralloc_header *child;
  65
  66    /* Linked list of siblings */
  67    struct ralloc_header *prev;
  68    struct ralloc_header *next;
  69
  70    void (*destructor)(void *);
  71 };
  72
  73 typedef struct ralloc_header ralloc_header;
  74
  75 static void unlink_block(ralloc_header *info);
  76 static void unsafe_free(ralloc_header *info);
  77
  78 static ralloc_header *
  79 get_header(const void *ptr)
  80 {
  81    ralloc_header *info = (ralloc_header *) (((char *) ptr) -
  82                                             sizeof(ralloc_header));
  83 #ifdef DEBUG
  84    assert(info->canary == CANARY);
  85 #endif
  86    return info;
  87 }
  88
  89 #define PTR_FROM_HEADER(info) (((char *) info) + sizeof(ralloc_header))
  90
  91 static void
  92 add_child(ralloc_header *parent, ralloc_header *info)
  93 {
  94    if (parent != NULL) {
  95       info->parent = parent;
  96       info->next = parent->child;
  97       parent->child = info;
  98
  99       if (info->next != NULL)
 100          info->next->prev = info;
 101    }
 102 }
 103
 104 void *
 105 ralloc_context(const void *ctx)
 106 {
 107    return ralloc_size(ctx, 0);
 108 }
 109
 110 void *
 111 ralloc_size(const void *ctx, size_t size)
 112 {
 113    void *block = calloc(1, size + sizeof(ralloc_header));
 114    ralloc_header *info;
 115    ralloc_header *parent;
 116
 117    if (unlikely(block == NULL))
 118       return NULL;
 119    info = (ralloc_header *) block;
 120    parent = ctx != NULL ? get_header(ctx) : NULL;
 121
 122    add_child(parent, info);
 123
 124 #ifdef DEBUG
 125    info->canary = CANARY;
 126 #endif
 127
 128    return PTR_FROM_HEADER(info);
 129 }
 130
 131 void *
 132 rzalloc_size(const void *ctx, size_t size)
 133 {
 134    void *ptr = ralloc_size(ctx, size);
 135    if (likely(ptr != NULL))
 136       memset(ptr, 0, size);
 137    return ptr;
 138 }
 139
 140 /* helper function - assumes ptr != NULL */
 141 static void *
 142 resize(void *ptr, size_t size)
 143 {
 144    ralloc_header *child, *old, *info;
 145
 146    old = get_header(ptr);
 147    info = realloc(old, size + sizeof(ralloc_header));
 148
 149    if (info == NULL)
 150       return NULL;
 151
 152    /* Update parent and sibling's links to the reallocated node. */
 153    if (info != old && info->parent != NULL) {
 154       if (info->parent->child == old)
 155          info->parent->child = info;
 156
 157       if (info->prev != NULL)
 158          info->prev->next = info;
 159
 160       if (info->next != NULL)
 161          info->next->prev = info;
 162    }
 163
 164    /* Update child->parent links for all children */
 165    for (child = info->child; child != NULL; child = child->next)
 166       child->parent = info;
 167
 168    return PTR_FROM_HEADER(info);
 169 }
 170
 171 void *
 172 reralloc_size(const void *ctx, void *ptr, size_t size)
 173 {
 174    if (unlikely(ptr == NULL))
 175       return ralloc_size(ctx, size);
 176
 177    assert(ralloc_parent(ptr) == ctx);
 178    return resize(ptr, size);
 179 }
 180
 181 void *
 182 ralloc_array_size(const void *ctx, size_t size, unsigned count)
 183 {
 184    if (count > SIZE_MAX/size)
 185       return NULL;
 186
 187    return ralloc_size(ctx, size * count);
 188 }
 189
 190 void *
 191 rzalloc_array_size(const void *ctx, size_t size, unsigned count)
 192 {
 193    if (count > SIZE_MAX/size)
 194       return NULL;
 195
 196    return rzalloc_size(ctx, size * count);
 197 }
 198
 199 void *
 200 reralloc_array_size(const void *ctx, void *ptr, size_t size, unsigned count)
 201 {
 202    if (count > SIZE_MAX/size)
 203       return NULL;
 204
 205    return reralloc_size(ctx, ptr, size * count);
 206 }
 207
 208 void
 209 ralloc_free(void *ptr)
 210 {
 211    ralloc_header *info;
 212
 213    if (ptr == NULL)
 214       return;
 215
 216    info = get_header(ptr);
 217    unlink_block(info);
 218    unsafe_free(info);
 219 }
 220
 221 static void
 222 unlink_block(ralloc_header *info)
 223 {
 224    /* Unlink from parent & siblings */
 225    if (info->parent != NULL) {
 226       if (info->parent->child == info)
 227          info->parent->child = info->next;
 228
 229       if (info->prev != NULL)
 230          info->prev->next = info->next;
 231
 232       if (info->next != NULL)
 233          info->next->prev = info->prev;
 234    }
 235    info->parent = NULL;
 236    info->prev = NULL;
 237    info->next = NULL;
 238 }
 239
 240 static void
 241 unsafe_free(ralloc_header *info)
 242 {
 243    /* Recursively free any children...don't waste time unlinking them. */
 244    ralloc_header *temp;
 245    while (info->child != NULL) {
 246       temp = info->child;
 247       info->child = temp->next;
 248       unsafe_free(temp);
 249    }
 250
 251    /* Free the block itself.  Call the destructor first, if any. */
 252    if (info->destructor != NULL)
 253       info->destructor(PTR_FROM_HEADER(info));
 254
 255    free(info);
 256 }
 257
 258 void
 259 ralloc_steal(const void *new_ctx, void *ptr)
 260 {
 261    ralloc_header *info, *parent;
 262
 263    if (unlikely(ptr == NULL))
 264       return;
 265
 266    info = get_header(ptr);
 267    parent = get_header(new_ctx);
 268
 269    unlink_block(info);
 270
 271    add_child(parent, info);
 272 }
 273
 274 void
 275 ralloc_adopt(const void *new_ctx, void *old_ctx)
 276 {
 277    ralloc_header *new_info, *old_info, *child;
 278
 279    if (unlikely(old_ctx == NULL))
 280       return;
 281
 282    old_info = get_header(old_ctx);
 283    new_info = get_header(new_ctx);
 284
 285    /* If there are no children, bail. */
 286    if (unlikely(old_info->child == NULL))
 287       return;
 288
 289    /* Set all the children's parent to new_ctx; get a pointer to the last child. */
 290    for (child = old_info->child; child->next != NULL; child = child->next) {
 291       child->parent = new_info;
 292    }
 293
 294    /* Connect the two lists together; parent them to new_ctx; make old_ctx empty. */
 295    child->next = new_info->child;
 296    new_info->child = old_info->child;
 297    old_info->child = NULL;
 298 }
 299
 300 void *
 301 ralloc_parent(const void *ptr)
 302 {
 303    ralloc_header *info;
 304
 305    if (unlikely(ptr == NULL))
 306       return NULL;
 307
 308    info = get_header(ptr);
 309    return info->parent ? PTR_FROM_HEADER(info->parent) : NULL;
 310 }
 311
 312 static void *autofree_context = NULL;
 313
 314 static void
 315 autofree(void)
 316 {
 317    ralloc_free(autofree_context);
 318 }
 319
 320 void *
 321 ralloc_autofree_context(void)
 322 {
 323    if (unlikely(autofree_context == NULL)) {
 324       autofree_context = ralloc_context(NULL);
 325       atexit(autofree);
 326    }
 327    return autofree_context;
 328 }
 329
 330 void
 331 ralloc_set_destructor(const void *ptr, void(*destructor)(void *))
 332 {
 333    ralloc_header *info = get_header(ptr);
 334    info->destructor = destructor;
 335 }
 336
 337 char *
 338 ralloc_strdup(const void *ctx, const char *str)
 339 {
 340    size_t n;
 341    char *ptr;
 342
 343    if (unlikely(str == NULL))
 344       return NULL;
 345
 346    n = strlen(str);
 347    ptr = ralloc_array(ctx, char, n + 1);
 348    memcpy(ptr, str, n);
 349    ptr[n] = '\0';
 350    return ptr;
 351 }
 352
 353 char *
 354 ralloc_strndup(const void *ctx, const char *str, size_t max)
 355 {
 356    size_t n;
 357    char *ptr;
 358
 359    if (unlikely(str == NULL))
 360       return NULL;
 361
 362    n = strlen(str);
 363    if (n > max)
 364       n = max;
 365
 366    ptr = ralloc_array(ctx, char, n + 1);
 367    memcpy(ptr, str, n);
 368    ptr[n] = '\0';
 369    return ptr;
 370 }
 371
 372 /* helper routine for strcat/strncat - n is the exact amount to copy */
 373 static bool
 374 cat(char **dest, const char *str, size_t n)
 375 {
 376    char *both;
 377    size_t existing_length;
 378    assert(dest != NULL && *dest != NULL);
 379
 380    existing_length = strlen(*dest);
 381    both = resize(*dest, existing_length + n + 1);
 382    if (unlikely(both == NULL))
 383       return false;
 384
 385    memcpy(both + existing_length, str, n);
 386    both[existing_length + n] = '\0';
 387
 388    *dest = both;
 389    return true;
 390 }
 391
 392
 393 bool
 394 ralloc_strcat(char **dest, const char *str)
 395 {
 396    return cat(dest, str, strlen(str));
 397 }
 398
 399 bool
 400 ralloc_strncat(char **dest, const char *str, size_t n)
 401 {
 402    /* Clamp n to the string length */
 403    size_t str_length = strlen(str);
 404    if (str_length < n)
 405       n = str_length;
 406
 407    return cat(dest, str, n);
 408 }
 409
 410 char *
 411 ralloc_asprintf(const void *ctx, const char *fmt, ...)
 412 {
 413    char *ptr;
 414    va_list args;
 415    va_start(args, fmt);
 416    ptr = ralloc_vasprintf(ctx, fmt, args);
 417    va_end(args);
 418    return ptr;
 419 }
 420
 421 /* Return the length of the string that would be generated by a printf-style
 422  * format and argument list, not including the \0 byte.
 423  */
 424 static size_t
 425 printf_length(const char *fmt, va_list untouched_args)
 426 {
 427    int size;
 428    char junk;
 429
 430    /* Make a copy of the va_list so the original caller can still use it */
 431    va_list args;
 432    va_copy(args, untouched_args);
 433
 434 #ifdef _WIN32
 435    /* We need to use _vcsprintf to calculate the size as vsnprintf returns -1
 436     * if the number of characters to write is greater than count.
 437     */
 438    size = _vscprintf(fmt, args);
 439    (void)junk;
 440 #else
 441    size = vsnprintf(&junk, 1, fmt, args);
 442 #endif
 443    assert(size >= 0);
 444
 445    va_end(args);
 446
 447    return size;
 448 }
 449
 450 char *
 451 ralloc_vasprintf(const void *ctx, const char *fmt, va_list args)
 452 {
 453    size_t size = printf_length(fmt, args) + 1;
 454
 455    char *ptr = ralloc_size(ctx, size);
 456    if (ptr != NULL)
 457       vsnprintf(ptr, size, fmt, args);
 458
 459    return ptr;
 460 }
 461
 462 bool
 463 ralloc_asprintf_append(char **str, const char *fmt, ...)
 464 {
 465    bool success;
 466    va_list args;
 467    va_start(args, fmt);
 468    success = ralloc_vasprintf_append(str, fmt, args);
 469    va_end(args);
 470    return success;
 471 }
 472
 473 bool
 474 ralloc_vasprintf_append(char **str, const char *fmt, va_list args)
 475 {
 476    size_t existing_length;
 477    assert(str != NULL);
 478    existing_length = *str ? strlen(*str) : 0;
 479    return ralloc_vasprintf_rewrite_tail(str, &existing_length, fmt, args);
 480 }
 481
 482 bool
 483 ralloc_asprintf_rewrite_tail(char **str, size_t *start, const char *fmt, ...)
 484 {
 485    bool success;
 486    va_list args;
 487    va_start(args, fmt);
 488    success = ralloc_vasprintf_rewrite_tail(str, start, fmt, args);
 489    va_end(args);
 490    return success;
 491 }
 492
 493 bool
 494 ralloc_vasprintf_rewrite_tail(char **str, size_t *start, const char *fmt,
 495                               va_list args)
 496 {
 497    size_t new_length;
 498    char *ptr;
 499
 500    assert(str != NULL);
 501
 502    if (unlikely(*str == NULL)) {
 503       // Assuming a NULL context is probably bad, but it's expected behavior.
 504       *str = ralloc_vasprintf(NULL, fmt, args);
 505       return true;
 506    }
 507
 508    new_length = printf_length(fmt, args);
 509
 510    ptr = resize(*str, *start + new_length + 1);
 511    if (unlikely(ptr == NULL))
 512       return false;
 513
 514    vsnprintf(ptr + *start, new_length + 1, fmt, args);
 515    *str = ptr;
 516    *start += new_length;
 517    return true;
 518 }